NARRATOR: How can you make sound visible? Can you make a work about sound that is totally silent? Look closely at the metal sculptures by artist and musician Terry Adkins. What you see here are 3D representations of the sound waves of birdcalls. Starting from the wall, you can follow the pattern of the birdcall. The thicker parts represent the loudest part of the birdsong and the narrowest part is the quietest part. Notice how some of the birds sing continuously, while others pause or repeat their songs.